Assessment of photo-induced cytotoxic activity of cachrys sicula and cachrys libanotis enriched-coumarin extracts against human melanoma cells

Could a humble Mediterranean plant hold the key to a smarter, light-activated attack on melanoma? New research suggests yes—by turning sunlight into a weapon against skin cancer cells.

Photochemotherapy—using light to activate a drug—is emerging as a powerful strategy against melanoma, the deadliest form of skin cancer. Now, scientists have turned to two wild plants from Southern Italy, Cachrys sicula and Cachrys libanotis, to find new photoactive compounds. Their coumarin-rich extracts, obtained via traditional maceration and a pressurized cyclic solid-liquid (PCSL) technique using the Naviglio extractor®, were tested on C32 melanoma cells under UVA irradiation (1.08 J/cm²).

Chemical analysis identified three furanocoumarins: xanthotoxin, bergapten, and isopimpinellin. All extracts showed concentration-dependent photocytotoxicity, with IC50 values between 3.16 and 18.18 µg/mL. The C. libanotis extract from PCSL was the most potent (IC50 = 3.16 ± 0.21 µg/mL), followed closely by its C. sicula counterpart (IC50 = 8.83 ± 0.20 µg/mL).

Beyond killing cells, these PCSL extracts triggered apoptosis—programmed cell death—by upregulating BAX and PARP cleavage, and increased p21 protein levels under UVA. The results suggest these plants are promising candidates for future photochemotherapy drugs, turning a sunny day into a potential cancer treatment.

Key Points

• Cachrys extracts show photocytotoxicity on melanoma cells.
• PCSL extraction yields most potent coumarin-rich samples.
• UVA triggers apoptosis via BAX, PARP, and p21 upregulation.